Protective apparatus for double string installations



K. A. HAWLEY 1,983,903

PROTECTIVE APPARATUS FOR DOUBLE STRING INSTALLATIONS Filed May 13, 1951 3 Sheets-Sheet 1 Dec. 11, I934.

@776 Hair /y K. A. HAWLEY 1,983,903

PROTECTIVE APPARATUS FOR DOUBLE STRING INSTALLATIONS Dec. 11, 1934.

Filed May 13, 1931 3 Sheets-Sheet 2 Deci 1 1, 1934. A, HAWLEY 1,983,903

PKOTECTIVE APPARATUS FOR DOUBLE STRING INSTALLATIONS Filed May 13, 1931 s Sheets-Sheet a l D H I w 24 @553;

Jwvmtoa K7977 Haw Patented Dec. 11, 1934 UNITED STATES PROTECTIVE APPARATUS FOR DOUBLE STRING INSTALLATIONS Kent A. Hawley, Locke Insulator Baltimore, Md., assignor to Corporation, Baltimore, Md.,

a corporation of Maryland Application May 13, 1931, Serial No. 537,174

11 Claims.

The invention relates to protective devices for transmission lines, particularly to that type of installation in which a conductor is supported by multiple strings of insulators arranged 5 either in parallel relation or in downwardly diverging relation.

The principal object of the invention, generally stated, is to provide arcing and grading devices located at the upper and lower ends of the double strings of insulators and cooperating to provide a path outwardly of the strings for an are which forms in the event of a flashover resulting from a sudden abnormal surge along the line.

It is well known that it is a common plan to rovide arcing horns or some other suitable electrode at the upper end of a single string of insulators cooperating with a grading ring or other equivalent electrode at the lower end of the string to provide a path for a flash-over. It is the principal purpose of the present invention to provide an equivalent protective means for use in connection with double strings.

A more specific object of the invention is to provide arcing and grading devices at the upper ends of a pair of insulator strings and acting, to all intents and purposes, as one and cooperating with similarly constructed means at the lower end of the strings, in the event that the 30 strings depend in parallel relation, or cooperating with a conventional type of grading ring or electrode at the lower ends of the respective strings in the event that the lower ends are widely separated as in an installation where the strings diverge downwardly.

A still more specific object of the invention is to provide an arcing and grading device of substantially U-shape so that they may be installed at the ends of a pair of strings of insulators with their bight portions arranged outwardly and their open sides toward each other for obtaining the same effect as if the devices were of continuous circular or ellipticalform as is common.

Another object of the invention is to provide a novel means for mounting the arcing devices upon the insulator strings, the construction of those to be mounted at the top of the strings 50 being naturally different from the detailed arrangement of those used at the lower end.

Another object of the invention is to provide protective devices of this character which may be conveniently formed from strap metal which may be simply bent to shape and the various parts secured without it being necessary to provide elaborate and expensive castings.

Still another object is to provide a protective apparatus of this character which on account of its extremely light construction will have but little inertia.

An additional object is to provide an installation of this character which will be simple and inexpensive to make, easy to apply, positive in action, efiicient and durable in service, and a general improvement in the art.

To the attainment of the foregoing and other objects and advantages, the invention preferably consists in the details of construction and the arrangement and combination of parts to be hereinafter more fully described and claimed, and illustrated in the accompanying drawings in which:

Figure 1 is an elevation of my apparatus showing it installed at the upper and lower ends of a pair of strings of insulators, the latter being represented diagrammatically, arranged in parallel depending relation,

Figure 2 is an elevation to Figure 1,

Figure 3 is an elevation showing the equipment applied to a pair of insulator strings arranged in downwardly diverging relation,

Figure 4 is a plan view of the upper electrodes,

Figure 5 is a detail plan view of one of the electrode members at the top of the string,

Figure 6 is a detail side elevation thereof, and

Figure '7 is a detail view taken on the line 7-7 of Figure 5.

Referring more particularly to the drawings I have shown a pair of protective devices indicated as a whole by the numeral 10 mounted at the upper ends of a pair of strings 11 of insulators of the suspension type here represented as of that particular variety equipped with metallic caps 12. Insulators of this character are provided at their undersides with pins of some sort or other, the arrangement being such that the pin of each is connected by some means or other with the cap of the one next below. Frequently the connection may consist of a ball and socket or simply clevises or ears pivotally connected. All such minor details do not enter into the essence of the present invention which has to do only with means for protecting the insulators against flash-overs resulting from lightning discharges or other abnormal surges along the line. Only the uppermost and lowermost units of each string are represented and the numeral 13 designates a pin depending from the lowermost unit.

taken at right angles It is of course customary to provide clamps 14 suspended from the strings for supporting the conductor 15.

In carrying out my invention it will be seen that the members 10 at the upper ends of the strings may be of the same construction regardless of whether the strings be arranged in' parallel relation as shown in Figures 1 and 2 or be arranged in diverging relation as shown in Figure 3, there being, however, a diiference between the forms of equipment used at the lower ends of the strings.

Each of the upper electrodes 10 is disclosed as comprising a substantially U-shaped member 16 having its arms 17 preferably slightly deflected laterally. Connecting the arms at the beginning of the bight portion is a Z-shaped bar or strip 18 having its central portion laterally curved into substantially semicircular shape as shown at 19 to definea saddle element or portion adapted to bedisposed against the cap 12 of the uppermost unit in the string. Cooperating and mating with the saddle portion 19 is a similarly shaped clamp member 20 adapted likewise to engage the cap and to clampingly engage the same by virtue of bolts 21 equipped with nuts 22. The portion 19 and member 20 together with the bolts 21 and nuts 22 constitute simply a clamping means which will embrace the uppermost cap and thereby effect secure mounting of the protective device. The arms 17 are preferably curved as shown so that the devices 10 may be used to equal advantage on a parallel installation as shown in Figure, l or in a divergent installation as shown in Figure 3, the arrangement of course being such, in either instance, that the arms 17 overlap so that the two protective devices at the upper ends of the strings will form, in effect, an elongated loop surrounding but spaced from the insulators.

The plain holding means above described may be entirely sufficient but as an additional refinement I may provide angular brackets 23 located between the 2 bar 18 andthe ends of the clamp 22 and held in place by the bolts 21, these brackets having tooth-like projections 24 engaging beneath the beveled lower edge of the uppermost cap 12, thereby positively and absolutely preventing the devices 10 from becoming dislodged under any circumstances. These auxiliary bracket devices are clearly illustrated in Figures 6 and 7.

Referring to the form of the invention shown in Figures 1 and 2, at the lower end of each string I provide a protective device 25 formed of U-shaped members 26 similar to the members 16 and having slightly laterally deflected arms 27 which overlap as shown so that the two devices 26 will constitute in effect an elongated loop. The means for attaching these devices 25 to the insulator strings may comprise a. transverse yoke 28' suitably secured to the arms 2'? and carrying spaced upstanding ears 29 secured. as by a pin or bolt 30 to the pin 13 depending from the lowermost insulator in the string. Secured to the underside of the member 28 at its center is a bracket 31 carrying a depending member 32 from which the above mentioned clamp 14 is suspended by suitable pivot means 33. This installation is of course the same for each one of the strings 11.

In the form of the invention shown in Figures 1 and 2 it is apparent that the two protective devices 10 at the upper ends of the strings will act as though they were one, as willalso the two protective devices 25 at the lower ends. These assembled devices at the two ends operate to grade and stabilize the electrical field about the insulators in a manner well recognized in the art. Furthermore in the event of a lightning discharge onto the line or any other similar unusual condition of surge when there is a flashover, the flash will occur between the devices 10 and 25 and as the path provided by them is outwardly beyond the insulator strings the in-- sulators themselves will not be damaged.

Where the strings are arranged in downwardly diverging relation, as shown in Figure 3, the devices 25 at the lower ends of the strings are made of circular form instead of U-shape though in other respects their construction may be identical with the devices 25. Of course in such an instance elongated suspension elements 34 must be provided between the clamps 14 and the lower protective devices in order that the edges of the latter will properly clear the conductor.

This second form of the invention operates in the same manner as the first form, the only difference being that the grading ring or electrode at the lower end of each string is continuous instead of there being two of U-shape mating to define the elongated loop.

From the foregoing description and a study of the drawings it will be apparent that I have thus provided a very simply constructed apparatus which may be easily installed and rigidly mounted, which may be manufactured by simple bending operations instead of elaborate casting, and which will yet eiiiciently protect the insulator strings. Another advantage is that this installation very simply solves the problem of providing electrodes of suitable character at the upper ends of double string installations wherein the distance between the strings is insufficient to permit the use of the ordinary continuous type of ring. Furthermore it will be clear that the same electrodes are used at the top of the strings regardless of whether they are parallel or divergent, this feature being of advantage as reducing the number of devices necessary to be kept on hand for installation in different types of equipment. It is thought that the construction, operation and advantages should be readily apparent to one skilled in the art from the foregoing without further explanation.

While I have shown and described the preferred embodiments of the invention, it should be understood that the disclosure is merely an exemplification of the principles involved as the right is reserved to make all such changes in the details of construction as will widen the field of utility and increase the adaptability of the device provided such changes constitute no departure from the spirit of the invention or the scope'of the-claims hereunto appended.

. Having thus described the invention, I claim:

1. In combination with a pair of insulator strings for suspending a conductor from a grounded support, protective means comprising separate electrodes mounted at the upper ends of the respective strings in electrical connection with the ground and cooperating with each other to define in eifect a single continuous electrode extending. outwardly about both strings, and separate'coacting electrodes at the lower ends of the respective strings in electrical connection with the conductor and providing with the first named electrodes a path for a flash-over.

2. In combination with a pair of insulator strings for suspending a conductor from a grounded support, protective means comprising separate individual overlapping electrodes mounted at the upper ends of the respective strings in electrical connection with the ground and cooperating with each other to define in effeet a single continuous electrode surrounding both strings, and coacting electrodes at the lower ends of the strings in electrical connection with the conductor and providing with the first named electrodes a path for a flash-over, the electrodes at the upper ends of the strings being counterparts of each other and those at the lower ends of the strings being likewise counterparts of each other.

3. In combination with a pair of insulator strings for suspending a conductor from a grounded support, protective means comprising electrodes mounted at the upper ends of the respective strings in electrical connection with the ground and cooperating with each other to define in efiect a continuous electrode, and coacting electrodes at the lower ends of the strings in electrical connection with the conductor and providing with the first named electrodes a path for a flash-over, each of said first named electrodes comprising a substantially U-shaped member, the arms of both members being arranged in laterally overlapping relation.

4. In combination with a pair of insulator strings for suspending a conductor from a grounded support, protective means comprising electrodes mounted at the upper ends of the strings in electrical connection with the ground and cooperating with each other to define in effect a continuous electrode, and coacting electrodes at the lower ends of the strings in electrical connection with the conductor and providing with the first named electrodes a path for a flash-over, each of said first named electrodes comprising a substantially U-shaped member having upwardly curved free ends, the ends of both members being oifset and arranged in laterally overlapping relation.

5. In combination with a pair of insulator strings for suspending a conductor from a grounded support, protective means comprising electrodes mounted at the upper ends of the strings in electrical connection with the ground and cooperating with each other to define in efiect a continuous electrode, and coacting electrodes at the lower ends of the strings in electrical connection with the conductor and providing with the first named electrodes a path for a flash-over, each of said first named electrodes comprising a substantially U-shaped member having upwardly curved arms, the arms of both members being laterally offset and arranged in overlapping relation, the curvature of said arms enabling the devices to be used on either parallel or divergent strings of insulators.

6. In a protective apparatus for a plurality of strings of suspension insulators carried by a grounded support and each carrying a conductor, an electrode at the upper end of each string comprising a substantially U-shaped member extending outwardly of the string in spaced relation thereto, the U-shaped members on the respective strings overlapping, a transverse member carried by the intermediate portion of said U-shaped member and formed with a saddle portion, and a clamp mating with said saddle portion, the uppermost insulator in the string having a metal cap, and said saddle portion and clamp embracingly engaging said cap.

7. In a protective apparatus for a plurality of strings of suspension insulators carried by a grounded support and each carrying a conductor, an electrode at the upper end of each string comprising a U-shaped member extending outwardly of the string in spaced relation thereto, said members being juxtaposed, a transverse member carried by each loop forming member and formed with a saddle portion, and a clamp mating with said saddle portion, the uppermost insulator in the string having a metal cap, said saddle portion and clamp embracingly engaging said cap, and bracket elements on said transverse member engaging beneath the lower edge of the cap.

8. Separate electrodes constructed to be mounted at the upper ends of each of a pair of strings of insulators of the cap and pin type, comprising a U-shaped member with arms of equal length extending outwardly of the uppermost insulator of each string, a Z-bar extending across said U-shaped member and formed with a saddle portion at its center, and a clamp mating with said saddle portion and cooperating therewith to embrace the cap of the uppermost insulator.

9. Separate electrodes constructed to be mounted at the upper ends of each of a pair of strings of insulators of the cap and pin type, comprising a U-shaped member extending outwardly of the uppermost insulator, a Z-bar extending across said loop forming member and formed with a saddle portion at its center, a clamp mating with said saddle portion and cooperating therewith to embrace the cap of the uppermost insulator, and securing elements located between the Z-bar and the clamp and having projecting portions engaging beneath the edge of said cap, said U-shaped members having their arms overlapped but unconnected.

10. A protective apparatus for a pair of strings of insulators arranged in downwardly diverging relation comprising a substantially U-shaped electrode mounted at the upper end of each string, said electrodes having upwardly curved free ends overlapping in lateral relation, and circular electrodes surrounding the lower ends of the respective strings and coacting with the first named electrodes to provide paths for arcs in the event of a flash-over.

11. A protective apparatus for a pair of insulator strings arranged in spaced parallel relation, grounded at their upper ends and carrying a conductor at their lower ends, comprising a substantially U-shaped electrode mounted at the upper end of each string and grounded, said electrodes having their arms arranged in laterally overlapping relation, and a U-shaped electrode mounted at the lower end of each string in electrical connection with the conductor, said second named electrodes having their arms arranged in laterally overlapping relation.

KENT A. HAWLEY. 

